phil335
New Member
Hi everyone,
I'm new to the forum and joined primarily because I understood Neale Monks is a member, I've read his excellent articles about these fish online and subsequently bought his book "Brackish Water Fishes" which is excellent. I'd love to hear the experiences of anyone who is keeping these fish. I read about them, did my homework and waited patiently (about 3 years) until we'd finished decorating/renovating before going ahead and returning to the hobby I'd last enjoyed in the early 70s as a teenager. I've always loved catfish, and having read about the Columbian Shark I knew that was the one for me. So I now have four Shark Catfish in a Fluval 240L tank with a 305 filter, with aeration provided by an old Hy Flo pump (all things 70s are cool!!) I've had the fish for 9 months and they are now between 6-7" and a nice silver colour with erect fins. After discovering the root of high nitrate levels in the tank (my tap water reads 80ppm straight out of the tap) I purchased an RO filter about 6 weeks ago. I've gradually been increasing the salinity since they were purchased and it is now at 1.015. When the fish were young they would flick themselves on the gravel and glass, since the salt levels have increased they have stopped this completely.
Using an API saltwater test kit I consistently get the following readings:
PH: 7.8 Ammonia: 0 Nitrite: 0 Nitrate: 30ppm Temp is 26C.
After the RO filter has done it's work the Nitrate level is 10ppm before I add it to the tank. However I can't seem to get the level below 30ppm in the tank despite frequent water changes. I don't overfeed, 3 times a day and they eat very enthusiastically and quickly. I'm feeding them on Hikari sinking carnivore pellets, Hikari sinking wafers, chopped earthworms, and raw finely chopped beef heart. All of these they consume instantly and heartily. Should I get a nitrate filter to reduce the levels further as I'm wondering if it is stressing the fish?
So what is the problem apart from the nitrate? Well despite seeming very healthy, they spend all of their time up one end of the tank, either sitting together huddled around the filter intake pipe, or swimming up and down the glass. Only when they feed will they swim halfway along the tank, nervously, and returning quickly to the safety of their filter pipe. I have a couple of artificial plants in the tank and a plastic log which they like swimming through at feeding times. I realised early on that the fluorescent tubes that came with the tank were far too bright so I fitted a dimmable, waterproof, colour led strip light to the rear hood, so they have very subtle lighting. I've tried adding various different plants and artificial roots but they seem very sensitive to any kind of change so I've decided it's best to leave the decor as is. I also added a wavemaker at the opposite end of the tank but this just made them huddle together more tightly.
How can I improve their behaviour and help them to become less nervous and shy? We don't have kids, they are in a quite corner of the living room, and we don't make loud noises! Should I add another species of fish to the tank? Would this make them realise that it's "safe" up the other end of the tank? If so which species? I realise they will outgrow their current tank and that I will need to upgrade the tank size when the time is right. However despite reading many articles that state these fish need loads of swimming space, mine don't use the space they've got.
They are stunning fish - perhaps they are quite happy as they are and I'm worrying unnecessarily. So any thoughts,suggestions or other keepers' experiences would be most welcome. Thanks!
I'm new to the forum and joined primarily because I understood Neale Monks is a member, I've read his excellent articles about these fish online and subsequently bought his book "Brackish Water Fishes" which is excellent. I'd love to hear the experiences of anyone who is keeping these fish. I read about them, did my homework and waited patiently (about 3 years) until we'd finished decorating/renovating before going ahead and returning to the hobby I'd last enjoyed in the early 70s as a teenager. I've always loved catfish, and having read about the Columbian Shark I knew that was the one for me. So I now have four Shark Catfish in a Fluval 240L tank with a 305 filter, with aeration provided by an old Hy Flo pump (all things 70s are cool!!) I've had the fish for 9 months and they are now between 6-7" and a nice silver colour with erect fins. After discovering the root of high nitrate levels in the tank (my tap water reads 80ppm straight out of the tap) I purchased an RO filter about 6 weeks ago. I've gradually been increasing the salinity since they were purchased and it is now at 1.015. When the fish were young they would flick themselves on the gravel and glass, since the salt levels have increased they have stopped this completely.
Using an API saltwater test kit I consistently get the following readings:
PH: 7.8 Ammonia: 0 Nitrite: 0 Nitrate: 30ppm Temp is 26C.
After the RO filter has done it's work the Nitrate level is 10ppm before I add it to the tank. However I can't seem to get the level below 30ppm in the tank despite frequent water changes. I don't overfeed, 3 times a day and they eat very enthusiastically and quickly. I'm feeding them on Hikari sinking carnivore pellets, Hikari sinking wafers, chopped earthworms, and raw finely chopped beef heart. All of these they consume instantly and heartily. Should I get a nitrate filter to reduce the levels further as I'm wondering if it is stressing the fish?
So what is the problem apart from the nitrate? Well despite seeming very healthy, they spend all of their time up one end of the tank, either sitting together huddled around the filter intake pipe, or swimming up and down the glass. Only when they feed will they swim halfway along the tank, nervously, and returning quickly to the safety of their filter pipe. I have a couple of artificial plants in the tank and a plastic log which they like swimming through at feeding times. I realised early on that the fluorescent tubes that came with the tank were far too bright so I fitted a dimmable, waterproof, colour led strip light to the rear hood, so they have very subtle lighting. I've tried adding various different plants and artificial roots but they seem very sensitive to any kind of change so I've decided it's best to leave the decor as is. I also added a wavemaker at the opposite end of the tank but this just made them huddle together more tightly.
How can I improve their behaviour and help them to become less nervous and shy? We don't have kids, they are in a quite corner of the living room, and we don't make loud noises! Should I add another species of fish to the tank? Would this make them realise that it's "safe" up the other end of the tank? If so which species? I realise they will outgrow their current tank and that I will need to upgrade the tank size when the time is right. However despite reading many articles that state these fish need loads of swimming space, mine don't use the space they've got.
They are stunning fish - perhaps they are quite happy as they are and I'm worrying unnecessarily. So any thoughts,suggestions or other keepers' experiences would be most welcome. Thanks!
/www.fishlore.com/profile-columbianshark.htm
